static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
struct dentry *parent,
unsigned long timeout,
int do_now)
{
struct dentry *p;
pr_debug("parent %p %pd\n", parent, parent);
p = NULL;
while ((p = get_next_positive_dentry(p, parent))) {
pr_debug("dentry %p %pd\n", p, p);
if (d_mountpoint(p)) {
/* Can we umount this guy */
if (autofs4_mount_busy(mnt, p))
continue;
/* Can we expire this guy */
if (autofs4_can_expire(p, timeout, do_now))
return p;
}
}
return NULL;
}
static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
struct dentry *parent,
unsigned long timeout,
int do_now)
{
struct dentry *p;
DPRINTK("parent %p %.*s",
parent, (int)parent->d_name.len, parent->d_name.name);
p = NULL;
while ((p = get_next_positive_dentry(p, parent))) {
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
if (d_mountpoint(p)) {
if (autofs4_mount_busy(mnt, p))
continue;
if (autofs4_can_expire(p, timeout, do_now))
return p;
}
}
return NULL;
}
/*
* Check a directory tree of mount points for busyness
* The tree is not busy iff no mountpoints are busy
*/
static int autofs4_tree_busy(struct vfsmount *mnt,
struct dentry *top,
unsigned long timeout,
int do_now)
{
struct autofs_info *top_ino = autofs4_dentry_ino(top);
struct dentry *p;
pr_debug("top %p %pd\n", top, top);
/* Negative dentry - give up */
if (!simple_positive(top))
return 1;
p = NULL;
while ((p = get_next_positive_dentry(p, top))) {
pr_debug("dentry %p %pd\n", p, p);
/*
* Is someone visiting anywhere in the subtree ?
* If there's no mount we need to check the usage
* count for the autofs dentry.
* If the fs is busy update the expiry counter.
*/
if (d_mountpoint(p)) {
if (autofs4_mount_busy(mnt, p)) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
} else {
struct autofs_info *ino = autofs4_dentry_ino(p);
unsigned int ino_count = atomic_read(&ino->count);
/* allow for dget above and top is already dgot */
if (p == top)
ino_count += 2;
else
ino_count++;
if (d_count(p) > ino_count) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
}
}
/* Timeout of a tree mount is ultimately determined by its top dentry */
if (!autofs4_can_expire(top, timeout, do_now))
return 1;
return 0;
}
static int autofs4_tree_busy(struct vfsmount *mnt,
struct dentry *top,
unsigned long timeout,
int do_now)
{
struct autofs_info *top_ino = autofs4_dentry_ino(top);
struct dentry *p;
DPRINTK("top %p %.*s",
top, (int)top->d_name.len, top->d_name.name);
if (!simple_positive(top))
return 1;
p = NULL;
while ((p = get_next_positive_dentry(p, top))) {
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
if (d_mountpoint(p)) {
if (autofs4_mount_busy(mnt, p)) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
} else {
struct autofs_info *ino = autofs4_dentry_ino(p);
unsigned int ino_count = atomic_read(&ino->count);
d_invalidate(p);
if (p == top)
ino_count += 2;
else
ino_count++;
if (p->d_count > ino_count) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
}
}
if (!autofs4_can_expire(top, timeout, do_now))
return 1;
return 0;
}
/* Check a directory tree of mount points for busyness
* The tree is not busy iff no mountpoints are busy
*/
static int autofs4_tree_busy(struct vfsmount *mnt,
struct dentry *top,
unsigned long timeout,
int do_now)
{
struct autofs_info *top_ino = autofs4_dentry_ino(top);
struct dentry *p;
DPRINTK("top %p %.*s",
top, (int)top->d_name.len, top->d_name.name);
/* Negative dentry - give up */
if (!simple_positive(top))
return 1;
p = NULL;
while ((p = get_next_positive_dentry(p, top))) {
DPRINTK("dentry %p %.*s",
p, (int) p->d_name.len, p->d_name.name);
/*
* Is someone visiting anywhere in the subtree ?
* If there's no mount we need to check the usage
* count for the autofs dentry.
* If the fs is busy update the expiry counter.
*/
if (d_mountpoint(p)) {
if (autofs4_mount_busy(mnt, p)) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
} else {
struct autofs_info *ino = autofs4_dentry_ino(p);
unsigned int ino_count = atomic_read(&ino->count);
/*
* Clean stale dentries below that have not been
* invalidated after a mount fail during lookup
*/
d_invalidate(p);
/* allow for dget above and top is already dgot */
if (p == top)
ino_count += 2;
else
ino_count++;
if (p->d_count > ino_count) {
top_ino->last_used = jiffies;
dput(p);
return 1;
}
}
}
/* Timeout of a tree mount is ultimately determined by its top dentry */
if (!autofs4_can_expire(top, timeout, do_now))
return 1;
return 0;
}
/*
* Find an eligible tree to time-out
* A tree is eligible if :-
* - it is unused by any user process
* - it has been unused for exp_timeout time
*/
struct dentry *autofs4_expire_indirect(struct super_block *sb,
struct vfsmount *mnt,
struct autofs_sb_info *sbi,
int how)
{
unsigned long timeout;
struct dentry *root = sb->s_root;
struct dentry *dentry;
struct dentry *expired = NULL;
int do_now = how & AUTOFS_EXP_IMMEDIATE;
int exp_leaves = how & AUTOFS_EXP_LEAVES;
struct autofs_info *ino;
unsigned int ino_count;
if (!root)
return NULL;
now = jiffies;
timeout = sbi->exp_timeout;
dentry = NULL;
while ((dentry = get_next_positive_dentry(dentry, root))) {
spin_lock(&sbi->fs_lock);
ino = autofs4_dentry_ino(dentry);
/* No point expiring a pending mount */
if (ino->flags & AUTOFS_INF_PENDING)
goto cont;
managed_dentry_set_transit(dentry);
/*
* Case 1: (i) indirect mount or top level pseudo direct mount
* (autofs-4.1).
* (ii) indirect mount with offset mount, check the "/"
* offset (autofs-5.0+).
*/
if (d_mountpoint(dentry)) {
DPRINTK("checking mountpoint %p %.*s",
dentry, (int)dentry->d_name.len, dentry->d_name.name);
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 2;
if (dentry->d_count > ino_count)
goto next;
/* Can we umount this guy */
if (autofs4_mount_busy(mnt, dentry))
goto next;
/* Can we expire this guy */
if (autofs4_can_expire(dentry, timeout, do_now)) {
expired = dentry;
goto found;
}
goto next;
}
if (simple_empty(dentry))
goto next;
/* Case 2: tree mount, expire iff entire tree is not busy */
if (!exp_leaves) {
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 1;
if (dentry->d_count > ino_count)
goto next;
if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
expired = dentry;
goto found;
}
/*
* Case 3: pseudo direct mount, expire individual leaves
* (autofs-4.1).
*/
} else {
/* Path walk currently on this dentry? */
ino_count = atomic_read(&ino->count) + 1;
if (dentry->d_count > ino_count)
goto next;
expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
if (expired) {
dput(dentry);
goto found;
}
}
next:
managed_dentry_clear_transit(dentry);
cont:
spin_unlock(&sbi->fs_lock);
}
return NULL;
found:
DPRINTK("returning %p %.*s",
expired, (int)expired->d_name.len, expired->d_name.name);
ino = autofs4_dentry_ino(expired);
ino->flags |= AUTOFS_INF_EXPIRING;
init_completion(&ino->expire_complete);
spin_unlock(&sbi->fs_lock);
spin_lock(&autofs4_lock);
spin_lock(&expired->d_parent->d_lock);
spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
spin_unlock(&expired->d_lock);
spin_unlock(&expired->d_parent->d_lock);
spin_unlock(&autofs4_lock);
return expired;
}
